Thantri or Tantri is the Vedic head priest of Hindu temples in Kerala and a very few temples of coastal Karnataka in southern India.
Thantris Shrauta are Namboothiri Brahmins who have studied the ancient tantras, and Poorva Mimamsa -- (the earliest part of the Vedas), unlike other Brahmins in India who are Smarta and follow Vedanta (latter parts of the Vedas).
Thantris or Tantry have the sole right to conduct certain core rituals in temples of Kerala and Tulunadu.